This invention generally pertains to systems and methods for training pilots to fly in sudden-onset reduced-visibility conditions (conditions with flight visibility of 5 miles or less, such as Degraded Visual Environments (“DVE”), unexpected departure from Visual Metrological Conditions (“VMC”), entry into Inadvertent Instrument Meteorological Conditions (“IIMC”)). More specifically, the invention pertains to systems and methods that incorporate electrical control of the transparency of lens material to manually or automatically selectively occlude a pilot's vision to simulate the sudden onset of a reduced visibility environment.
The use of devices to restrict a pilot's vision to simulate reduced-visibility conditions for fly-by-instrument training is well known. Typically, the condition is simulated either by (1) using a device, such as glasses, a hood, or a visor, to restrict the pilot's view during a training flight or (2) controlling the visual environment in a flight simulator. Where the prior-art fails, however, is in providing a realistic simulation of an unexpected entry into a reduced-visibility environment, such as IIMC.
Improper pilot reaction to sudden-onset reduced visibility conditions results in significant loss of life, property, and business every year. Pilots, including specifically helicopter pilots, continue to unexpectedly enter reduced-visibility conditions. These events cause spatial disorientation and loss of aircraft control. These events often result in accidents, 70% of which are fatal. According to the National Transportation and Safety Board accident data, there were over 80 civilian helicopter accidents involving IIMC, with a 70% fatality rate and another 19% injury rate, in the time period between 2000 and 2014. Overall, 89% of the accidents involving IIMC result in injuries or fatalities. See National Transportation and Safety Board, Aviation Accident Database and Synopses , available at http://www.ntsb.gov/_layouts/ntsb.aviation/index.aspx. Based on the Department of Transportation's Guidance on Treatment of the Economic Value of a Statistical Life—2015 Adjustment, these accidents had a human cost of over $1.4 billion. See https://www.transportation.gov/sites/dot.gov/files/docs/VSL2015_0.pdf. This number does not include the related damage to property and equipment or lost revenue to business. The value of property, equipment, and business that was lost or harmed due to pilot response to the sudden onset of reduced-visibility conditions could exceed the $1.4 billion mark.
The accidents in sudden-onset reduced-visibility conditions are due in large part to the flawed procedures and technological limitations of pilot training. In the National Transportation and Safety Board's 2015 Most Wanted List of Transportation Safety Improvements report, enhanced public helicopter safety was a key issue. http://www.ntsb.gov/safety/mwl/Pages/mwl3_2015.aspx. Included in the report's recommendations were developing and implementing best practices for training flight crews for inadvertent flight into IMC conditions. The report also stated that training should be scenario-based. Unfortunately, there currently is no way to provide scenario-based training for Inadvertent IMC in an actual aircraft.
Currently there is no technology to simulate sudden-onset reduced-visibility conditions that provides the confusion, panic, disorientation and overall stress that comes when the visual environment is lost unexpectedly during flight. Research shows that surviving the first two minutes of the sudden-onset reduced-visibility event increases the survival rate significantly. This is the moment when the mental impact of the event is greatest. Current training techniques and equipment fail to prepare pilots to handle a sudden-onset reduced-visibility event because they fail to simulate the impact of the event on the pilot.
The most accepted technology for training pilots for sudden-onset reduced-visibility events, a flight simulator, does not properly prepare pilots for the actual event. This simulator training fails for a variety of reasons, including limited availability of simulator training, the simulator's failure to simulate the stress of an actual event, and the simulator's inability to simulate the spatial disorientation experienced in an actual event. Many pilots are rarely—if ever—able to use a simulator. And those pilots who have access to a simulator (typically commercial or military pilots) can use it at most a few times a year. Simulators do not effectively reproduce the stress of flying an actual aircraft where human life is at risk. This stress is an overwhelming factor in decision making during a true emergency. Perhaps most importantly—it is practically impossible to simulate spatial disorientation with a flight simulator. The signals the proprioceptive and vestibular systems send to the pilot's brain when the visual references are lost dictate how a pilot interprets an aircraft's attitude. Spatial disorientation is the leading cause of loss of control and is the single most important aspect that needs to be trained. The fact that most flight simulators today are non-motion simulators exacerbates the problem. Simply, these flight simulators do not accurately simulate a real-life sudden-onset reduced-visibility event.
Vision-restricting fly-by-instrument-training devices do not simulate the unexpected loss of the visual environment that leads to the stress and spatial disorientation of a sudden-onset reduced-visibility event. Because of this failing, aircraft (especially helicopters) continue to crash. People continue to die.
For example, U.S. Pat. No. 2,572,656 (“Ortenburger”) discloses a device comprising two filters, either alone transparent but that together are opaque. The device is situated on the pilot such that when viewing the horizon and flight path of the aircraft, the pilot looks through both filters and when viewing instruments in the aircraft, the pilot looks through only a single filter. Thus, the pilot is able to view the instruments but is unable to see outside the aircraft. But the pilot using the Ortenburger device knows that his visibility will be reduced by using the device. That is, the Ortenburger device, while it simulates reduced-visibility conditions, does not simulate unexpected entry into such conditions.
Another vision-limiting device is disclosed in U.S. Pat. No. 2,694,263 (“Francis et al.”). Like the Ortenburger device, the Francis et al. device is situated on the pilot to reduce visibility in certain directions. The Francis et al. device is generally opaque with transparent sections that allow the pilot to see the instruments or the horizon, but not both at once. But like the Ortenburger device, the Francis et al. device cannot replicate the disorientation that comes with unexpected entry into reduced visibility conditions because the pilot dons the device knowing that it will restrict her vision.
The vision limiting device disclosed in U.S. Pat. No. 4,021,935 (“Witt I”) uses an electronically controlled LCD lens to limit a pilot's visibility based on the direction the pilot is looking. The Witt I device determines the pilot's viewing direction by measuring the incident light on the device using a directed photocell. When the pilot looks at the aircraft's instruments, the photocell registers a low level of light and the lens is kept transparent. When the pilot looks to the horizon, the photocell registers a high level of light and the lens is made opaque. A similar device is disclosed in U.S. Pat. No. 4,152,846 (“Witt II”). The Witt II device uses multiple light sensors to better determine the pilot's viewing direction. The Witt I and Witt II devices cannot replicate the disorientation that comes with unexpected entry into reduced visibility conditions because the pilot dons the device knowing that it will restrict her vision when she looks at other than the instruments.
Another approach to reduced-visibility flight training is disclosed in U.S. Pat. No. 4,698,022 (“Gilson”). The Gilson device restricts the pilot's vision by placing a translucent material over glasses except for that portion of the glasses through which the pilot views the instruments. This reduces the pilot's vision other than to a narrow field designed to allow viewing of the aircraft instruments. The degree of translucency can be varied to simulate different visibility conditions by selecting different overlay materials. But the Gilson device fails to provide a mechanism to simulate unexpected entry into reduced visibility conditions because the pilot dons the device knowing that it will restrict her vision except for a narrow field.
Yet another approach to simulating reduced visibility conditions for pilots is disclosed in U.S. Patent Application Publication No. 2012/0156655 (“Goldberg”). The Goldberg device is a combination of a transparent polarized material to cover the windows of the cockpit and another transparent polarized material to cover the lens of a viewing shield such as glasses worn by the pilot. The window polarization is orthogonal to the lens polarization such that when the pilot dons the polarized viewing shield, he cannot see through the polarized windows. As with the previously described prior-art approaches, the Goldberg device fails to provide a mechanism to simulate unexpected entry into reduced visibility conditions because the pilot dons the device knowing that he will not be able to see outside the aircraft.
The prior-art approaches to simulating reduced-visibility conditions fail in at least one important way. They do not accurately simulate the confusion, panic, disorientation, proprioceptive, and vestibular sensations that come from unplanned entry into such conditions. That is, a pilot reacts differently to inadvertent entry into a reduced-visibility condition than she does to planned entry into such a condition. And this difference may leave the pilot unprepared for reality, regardless of her training, and reduce her ability to properly react in such conditions. Improper reaction to unexpected reduced-visibility conditions may lead to fatalities, injury, and property damage. The prior-art approaches do not adequately simulate inadvertent entry into reduced-visibility conditions.
Accordingly, there is a need for a system and method for more accurately simulating sudden-onset reduced-visibility events.